The influence of fatty acid chain length and saturation on cholesterol absorption in rats will be investigated. Groups of rats on semi-purified diets containing 10% triglyceride will be fed: hydrogenated coconut oil, trimyristin, tripalmitin, tristearin, triolein or safflower oil (plus EFA). Cholesterol absorption will be quantitated by the plasma dual isotope method of Zilversmit. Plasma cholesterol kinetic data will also be calculated in rats maintained on diets for 4-5 weeks after radiolabeled cholesterol dosage. Plasma and hepatic lipids will also be measured. These data will permit simultaneous evaluation of effects of pure triglycerides on cholesterol absorption and metabolism. BIBLIOGRAPHIC REFERENCES: Feldman, E.B., Russell, B., Fields, L. and Feldman, D.S. Effects of Surfactants and Lipids on Cholesterol Phase Partition. Abstracts, Council on Arteriosclerosis, November, 1976, p. 11.